Industry has identified two end uses for these products. The first is a high temperature light weight low loss dielectric material. High purity fused silica is a high temperature low loss dielectric material, but in and by itself is heavy. A scalable process for making HPFS® high purity fused silica glass porous would be highly desirable.
Regarding the second use, reducing the weight of mirror supports is vital for the future of the mirrors business. Two separate categories of light weighted mirrors are desired. First, they are vital for the space program which has stringent weight constraints. Second, large scale terrestrial bound mirrors (over a meter in size) also desire light weight supports in order to have better control over the maneuverability of the mirrors while in use. The mirror supports should not add any stresses to the actual mirror. One of the best ways of doing this is to make the mirror support out of the same material as the mirrors so that no stresses from thermal expansion mismatch develop.
Currently, mirrors are made of either high purity fused silica HPFS® fused silica glass or ULE® ultra-low expansion glass of Corning Incorporated, Corning, N.Y. 14830. An additional requirement is that the mirror material must also be environmentally stable.
The existing method for making supports first involves making dense glass. Secondly, the glass is machined into an intricate honeycomb-like pattern to remove most excess weight. Thirdly, the mirror is bonded to the fabricated honeycomb structure. A process for making porous glass without first making dense glass would be highly desirable.